Yellow Cupcakes with Chocolate Frosting

Adapted from http://smittenkitchen.com/2009/07/best-birthday-cake/


4 cups cake flour (not self-rising)
2 teaspoons baking powder
1 ½ teaspoons baking soda
1 teaspoon table salt
2 sticks unsalted butter, softened
2 cups sugar
2 teaspoons pure vanilla extract
3 large eggs + 2 egg yolks, at room temperature
2 cups buttermilk, well-shaken


Preheat oven to 350°F.


Sift together flour, baking powder, baking soda, and salt in a medium bowl. In a large mixing bowl, beat butter and sugar with an electric mixer at medium speed until pale and fluffy, then beat in vanilla. Add eggs 1 at a time, beating well and scraping down the bowl after each addition. At low speed, beat in buttermilk until just combined (mixture will look curdled). Add flour mixture in three batches, mixing until each addition is just incorporated.


Pour batter into each well of the muffin tin until it is about 2/3 full. Bake until golden and a wooden pick inserted in center of cake comes out clean, 14 minutes. Cool in muffin tin on a rack for two minutes, then remove the cupcakes from the tin to cool completely.

Chocolate Frosting

From http://annies-eats.com/2010/10/12/yellow-butter-cake-with-chocolate-frosting/

1 lb. semisweet chocolate, finely chopped
6 tbsp. Dutch-process cocoa powder
6 tbsp. boiling water
3 sticks (1½ cups) unsalted butter, at room temperature
½ cup confectioners’ sugar, sifted
Pinch of salt

To make the frosting, place the chocolate in a heatproof bowl set over a pan of simmering water.  Heat, stirring occasionally, until the chocolate has melted.  Remove from the heat and let cool to room temperature, about 25-30 minutes.  Meanwhile, combine the cocoa powder and boiling water in a small bowl; stir until the cocoa is dissolved.

In the bowl of an electric mixer, beat the butter, confectioners’ sugar and salt on medium-high speed until light and fluffy, 3-4 minutes.  Add the melted chocolate; beat on low speed until combined, 1-2 minutes.  Beat in the cocoa mixture until well blended. Cool frosting slightly before using if it is too runny.